It's amazing how quickly sometimes you can tell if there is any chemistry between the cast members when you watch a show for the first time.
When I first watched "Firefly", I could tell within the first 30 minutes of the pilot episode that Joss Whedon had "lightning in a bottle" concerning the chemistry between the crew members.
At the other end of the spectrum there's the Netflix show "Another Life" where there was almost zero chemistry between the crew members even after 10 episodes.